Second slice of the E11 keyboard layer (S4b). S4a gave the feed, the library and the channel page
`j`/`k`, the arrows and Enter; Home's shelves and the whole Plex module were still Tab-stop country —
a Plex poster is its own Tab stop, and a rail's cards sat behind every control of the cards before.
- `lib/listNav`: a list that mounts every item no longer declares a count or columns — both are
measured off the DOM when a key is pressed, so an auto-fill grid's columns follow its width and a
rail is one row. ↑ on a list's top row and ↓ on its bottom row go on to the neighbouring list, onto
the item horizontally nearest the one left (owner decision D4: ←→ within a rail, ↑↓ to the rail
above or below). The first `j` skips cards a rail has scrolled out to the left.
- `Carousel keyboardNav` registers the scroller; the scroller gets a 4px inset (against a -4px margin,
layout unchanged) so the focus ring is not clipped, and `[data-nav-index]` a 2.5rem inline scroll
margin so a card stepped into view clears the rail's edge fade and paging arrow.
- `ui/NavGrid`: the plain, fully mounted grid that registers itself.
- `navIndex` on PlexPosterCard / SeasonCard / EpisodeCard (the card root is the item, the poster the
open element — the ring goes round poster and title, D2), PosterTile and Home's ShelfTile (the button
is the item); cast, related and collection-strip buttons carry the attrs directly.
- Wired: Home's comfort and resume rails; Plex Browse titles + episodes, Discover rails + genres,
collection view, playlists/collections browse, person known-for + filmography, show seasons, season
episodes, cast/related strips, info-page cast + collection strips.
- `listNav.wiring.contract.test`: every `Carousel` says `keyboardNav`, every card says `navIndex`, and a
card with `navIndex` sits inside a NavGrid / Carousel / VirtualGrid — both halves are opt-in, and
either one missing leaves a list the keyboard silently skips.
The poster card (grid + person page) gets the Seerr-style hover: on hover a
bottom scrim slides up with the title, a "year · runtime · ★rating" meta line,
and a 3-line synopsis — the info you'd otherwise click through for — plus a
less-flat play ring (radial-gradient + ring shadow) and a top-right quick-action
cluster (Info + watched-toggle, revealed on hover / always on touch). Rest-state
badges (season / type tag) yield to the scrim on hover; the playable-cost tint
stays. (§1 A + C from the enrichment study.)
Backend (the data the scrim needs, mirroring S1's `art`): the grid
(browse.unified_library) now emits a lang-coalesced, truncated `summary` (new
query.summary_col) + the Plex `rating`; movie_card/show_card do the same (EN) for
the detail/related/person cards. PlexCard.rating type added (summary already
existed for episodes).
Gate: tsc x3 / eslint / prettier / knip / vitest 326 green; ruff green; backend
lane full suite green. Self-E2E on the live dev server (rebuilt on this branch,
S2-enriched): the grid serves rating+summary (Shawshank 9.3, Godfather 9.2, real
synopses) and the card renders the play ring + scrim (The Expanse: ring, synopsis,
★8.1) — verified via the DOM (the pane wouldn't composite for a screenshot).
Closes the re-review's test-coverage finding: a plexCards.dom.test asserting the
icon-only card controls (watched-toggle, Info, add-season/episode) each expose
their aria-label as an accessible name via getByRole({name}). A future edit that
drops a label now fails the gate instead of silently reopening the unnamed-button
gap the a11y sweep closed.
4 tests; full FE gate green (tsc/eslint/prettier/knip, 321 vitest).